Glaucoma is one of the major causes of blindness in the aging veteran population. Many veterans develop glaucomatous optic neuropathy even without being aware of the disease presence and frequently early glaucomatous changes present a major diagnostic challenge even with expert eye examination. Raman spectroscopy has been recently introduced as a novel imaging method for detection of subtle tissue biochemical changes in vivo and in vitro. Preliminary studies have demonstrated that Raman spectroscopy can be effectively used for detection of biochemical changes associated with glaucoma in vitro. The purpose of this research is to develop Raman spectroscopy routines which could be potentially used to detect early onset of glaucoma based on changes in tissue biochemical composition. This approach has a unique, high probability of success because: 1) A detailed characterization of biochemical Raman spectra in the canine nerve fiber layer, optic nerve head and retinal ganglion cells in retinal tissue sections has been performed, and demonstrated that biochemical spectra obtained by Raman spectroscopy are very reproducible; 2) It has been demonstrated that Raman spectroscopy is a sensitive method for detection of biochemical changes in tissue sections of the retina and optic nerve in dogs with glaucoma; 3) It has been demonstrated that Raman spectroscopy can be effectively used for detection of early biochemical changes in canine retina and optic nerve tissue sections after induction of compressive optic neuropathy or acute elevation of intraocular pressure; 4) A unique colony of dogs (Basset Hounds) with hereditary glaucoma has been developed, in which researchers can monitor progression of functional and structural optic nerve changes at different stages of disease by using sophisticated functional and structural optic nerve imaging. Hypothesis: The present proposal will determine whether Raman imaging can be used for detection of early glaucomatous changes in canine and human glaucomatous tissue even with low energy parameters, which could be used for in vivo imaging in the future. The successful outcome of this proposal will provide a new approach for early detection of glaucoma, which may help to initiate treatment much sooner to prevent development of blindness due to glaucoma in numerous aging veterans. The following specific aims will be addressed in this pilot project: Specific aim 1: Determine whether Raman spectroscopy can be used for detection of glaucomatous changes in retina and optic nerve sections from dogs with hereditary glaucoma with a different stage of disease. Specific Aim 2: Determine whether Raman spectroscopy can be used for discrimination of molecular changes in human retinal sections from patients with glaucoma and ocular hypertension, when compared to Raman spectroscopic properties from healthy donor tissues. PUBLIC HEALTH RELEVANCE: Glaucoma is one of the major causes of blindness in the aging veteran population. Many veterans develop glaucomatous optic neuropathy even without being aware of the disease presence and frequently early glaucomatous changes present a major diagnostic challenge even with expert eye examination. Raman spectroscopy has been recently introduced as a novel imaging method for detection of subtle tissue biochemical changes in vivo and in vitro. In our preliminary studies we have demonstrated that Raman spectroscopy can be effectively used for detection of biochemical changes associated with canine glaucoma in vitro. In this pilot project, we would like to evaluate whether a similar approach can be used for detection of biochemical changes in human glaucomatous retinas in vitro, with a focus on developing safe in vivo imaging routines in the future.